diff --git a/src/Backend.php b/src/Backend.php
index e5c7ab4..3c5592f 100644
--- a/src/Backend.php
+++ b/src/Backend.php
@@ -15,7 +15,6 @@ declare(strict_types=1);
 namespace Dotclear\Plugin\moreCSS;
 
 use dcAdmin;
-use dcAuth;
 use dcCore;
 use dcFavorites;
 use dcNsProcess;
@@ -32,7 +31,7 @@ class Backend extends dcNsProcess
 
     public static function process(): bool
     {
-        if (!static::$init) {
+        if (!static::$init || is_null(dcCore::app()->auth) || is_null(dcCore::app()->blog) || is_null(dcCore::app()->adminurl)) {
             return false;
         }
 
@@ -40,17 +39,20 @@ class Backend extends dcNsProcess
             My::name(),
             dcCore::app()->adminurl->get('admin.plugin.' . My::id()),
             [dcPage::getPF(My::id() . '/icon.png')],
-            preg_match('/' . preg_quote(dcCore::app()->adminurl->get('admin.plugin.' . My::id())) . '(&.*)?$/', $_SERVER['REQUEST_URI']),
-            dcCore::app()->auth->check(dcCore::app()->auth->makePermissions([dcAuth::PERMISSION_CONTENT_ADMIN]), dcCore::app()->blog->id)
+            preg_match('/' . preg_quote((string) dcCore::app()->adminurl->get('admin.plugin.' . My::id())) . '(&.*)?$/', $_SERVER['REQUEST_URI']),
+            dcCore::app()->auth->check(dcCore::app()->auth->makePermissions([dcCore::app()->auth::PERMISSION_CONTENT_ADMIN]), dcCore::app()->blog->id)
         );
 
         dcCore::app()->addBehavior('adminDashboardFavoritesV2', function (dcFavorites $favs): void {
+            if (is_null(dcCore::app()->auth) || is_null(dcCore::app()->adminurl)) {
+                return;
+            }
             $favs->register(My::id(), [
                 'title'       => My::name(),
                 'url'         => dcCore::app()->adminurl->get('admin.plugin.' . My::id()),
                 'small-icon'  => [dcPage::getPF(My::id() . '/icon.png')],
                 'large-icon'  => [dcPage::getPF(My::id() . '/icon-big.png')],
-                'permissions' => dcCore::app()->auth->makePermissions([dcAuth::PERMISSION_CONTENT_ADMIN]),
+                'permissions' => dcCore::app()->auth->makePermissions([dcCore::app()->auth::PERMISSION_CONTENT_ADMIN]),
             ]);
         });
 
diff --git a/src/Frontend.php b/src/Frontend.php
index 42c25fd..26f8724 100644
--- a/src/Frontend.php
+++ b/src/Frontend.php
@@ -29,11 +29,14 @@ class Frontend extends dcNsProcess
 
     public static function process(): bool
     {
-        if (!static::$init || !dcCore::app()->blog->settings->get('themes')->get('morecss_active')) {
+        if (!static::$init || is_null(dcCore::app()->blog) || !dcCore::app()->blog->settings->get('themes')->get('morecss_active')) {
             return false;
         }
 
         dcCore::app()->addBehavior('publicHeadContent', function (): void {
+            if (is_null(dcCore::app()->blog)) {
+                return;
+            }
             $css = (string) base64_decode((string) dcCore::app()->blog->settings->get('themes')->get('morecss_min'));
             if (!empty($css)) {
                 echo dcUtils::cssLoad(
diff --git a/src/Install.php b/src/Install.php
index f7327a1..3918d4f 100644
--- a/src/Install.php
+++ b/src/Install.php
@@ -30,7 +30,7 @@ class Install extends dcNsProcess
 
     public static function process(): bool
     {
-        if (!static::$init) {
+        if (!static::$init || is_null(dcCore::app()->blog)) {
             return false;
         }
 
diff --git a/src/Manage.php b/src/Manage.php
index 0e14179..45423c9 100644
--- a/src/Manage.php
+++ b/src/Manage.php
@@ -14,7 +14,6 @@ declare(strict_types=1);
 
 namespace Dotclear\Plugin\moreCSS;
 
-use dcAuth;
 use dcCore;
 use dcNsProcess;
 use dcPage;
@@ -35,8 +34,9 @@ class Manage extends dcNsProcess
     public static function init(): bool
     {
         static::$init = defined('DC_CONTEXT_ADMIN')
+            && !is_null(dcCore::app()->auth) && !is_null(dcCore::app()->blog)
             && dcCore::app()->auth->check(dcCore::app()->auth->makePermissions([
-                dcAuth::PERMISSION_CONTENT_ADMIN,
+                dcCore::app()->auth::PERMISSION_CONTENT_ADMIN,
             ]), dcCore::app()->blog->id);
 
         return static::$init;
@@ -44,7 +44,7 @@ class Manage extends dcNsProcess
 
     public static function process(): bool
     {
-        if (!static::$init) {
+        if (!static::$init || is_null(dcCore::app()->blog) || is_null(dcCore::app()->adminurl)) {
             return false;
         }
 
@@ -58,15 +58,15 @@ class Manage extends dcNsProcess
                 $s->put('morecss_active', !empty($_POST['morecss_active']));
 
                 // Minify it
-                $css_min = preg_replace('` {2,}`', ' ', $_POST['morecss']);
-                $css_min = preg_replace('/(\/\*[\s\S]*?\*\/)/', '', $css_min);
-                $css_min = preg_replace('/(\t|\r|\n)/', '', $css_min);
+                $css_min = (string) preg_replace('` {2,}`', ' ', $_POST['morecss']);
+                $css_min = (string) preg_replace('/(\/\*[\s\S]*?\*\/)/', '', $css_min);
+                $css_min = (string) preg_replace('/(\t|\r|\n)/', '', $css_min);
                 $css_min = str_replace([' { ', ' {', '{ '], '{', $css_min);
                 $css_min = str_replace([' } ', ' }', '} '], '}', $css_min);
                 $css_min = str_replace([' : ', ' :', ': '], ':', $css_min);
                 $css_min = str_replace([' ; ', ' ;', '; '], ';', $css_min);
                 $css_min = str_replace([' , ', ' ,', ', '], ',', $css_min);
-                $s->put('morecss_min', is_string($css_min) ? base64_encode($css_min) : '');
+                $s->put('morecss_min', base64_encode($css_min));
 
                 dcPage::addSuccessNotice(
                     __('Configuration successfully updated.')
@@ -84,7 +84,7 @@ class Manage extends dcNsProcess
 
     public static function render(): void
     {
-        if (!static::$init) {
+        if (!static::$init || is_null(dcCore::app()->auth) || is_null(dcCore::app()->auth->user_prefs) || is_null(dcCore::app()->blog)) {
             return;
         }
 
@@ -113,7 +113,7 @@ class Manage extends dcNsProcess
                 (new Textarea('morecss', Html::escapeHTML((string) base64_decode((string) $s->get('morecss')))))->class('maximal')->cols(72)->rows(25),
             ]),
             (new Para())->items([
-                (new Checkbox('morecss_active'))->value(1),
+                (new Checkbox('morecss_active', (bool) $s->get('morecss_active')))->value(1),
                 (new Label(__('Enable additionnal CSS for the active theme'), Label::OUTSIDE_LABEL_AFTER))->for('morecss_active')->class('classic'),
             ]),
             (new Para())->items([
diff --git a/src/Prepend.php b/src/Prepend.php
index d3b8bee..c2ebcf7 100644
--- a/src/Prepend.php
+++ b/src/Prepend.php
@@ -37,6 +37,9 @@ class Prepend extends dcNsProcess
             'morecss.css',
             '^morecss\.css(.*?)$',
             function (string $args): void {
+                if (is_null(dcCore::app()->blog)) {
+                    return;
+                }
                 header('Content-Type: text/css; charset=UTF-8');
 
                 echo "/* CSS for plugin moreCss */ \n";